Use of α‐aminoadipate and lysine as sole nitrogen source by Schizosacharomyces pombe and selected pathogenic fungi

α‐Aminodipate, an intermediate of the lysine biosynthetic pathway of fungi, or lysine when used as the sole nitrogen source in the medium was growth inhibitory and toxic to Saccharomyces cerevisiae. The fission yeast Schizosaccharomyces pombe and pathogenic fungi Candida albicans, Filobasidiella neoformans and Aspergillus fumigatus grew in the medium containing α‐aminoadipate as the sole nitrogen source. C. albicans, A. fumigatus , and one of the strains of F. neoformans also grew in the medium containing lysine as the sole nitrogen source. When grown in the α‐aminoadipate medium, only S. pombe accumulated a significant amount of α‐ketoadipate in the culture supernatant. Also, 14 C‐α‐aminoadipate was converted to 14 C‐α‐ketoadipate in vivo. In the ammonium sulfate medium, S. pombe cells converted 14 C‐α‐aminoadipate to lysine. The levels of glutamate‐α‐ketoadipate transaminase, an enzyme responsible for the conversion of α‐aminoadipate to α‐ketoadipate, and α‐aminoadipate reductase, an enzyme required for the conversion of α‐aminoadipate to lysine, were similar in S. pombe cells grown in the α‐aminoadipate or ammonium sulfate medium. However, the level of homoisocitrate dehydrogenase, an enzyme before the α‐ketoadipate step, was twelvefold lower in S. pombe cells grown in the α‐aminoadipate medium compared to the level in cells grown in the ammonium sulfate medium. Pathogenic fungi used in this study did not accumulate α‐ketoadipate and α‐aminoadipate‐δ‐semialdehyde when grown in medium containing α‐aminoadipate and lysine, respectively, as sole nitrogen source. However, only pathogenic fungi used both lysine and α‐aminoadipate as sole nitrogen source. This unique metabolic property could be useful for the identification of these pathogens.